Fig. 1

The phenotypic characterization of hUC-MSCs at various passages. a Phase contrast images of hUC-MSCs at various passages (P3, P6, P15) in DMEM/F12 medium containing 10% FBS, 1% l-glutamine, 1% NEAA, and 1% penicillin-streptomycin (short for 10% FBS/DF12 medium thereafter). Scale bar = 200 μm. b Flow cytometry (FCM) analysis of MSC markers of hUC-MSCs at various passages (P3, P6, P15) cultured in 10% FBS/DF12 medium (mean ± SEM, n = 3). NS, not significant. c Proliferation assay of hUC-MSCs at various passages (P3, P6, P15) cultured in 10% FBS/DF12 medium for 7 days (mean ± SEM, n = 3). *P < 0.05. Cell cycle (d) and cell apoptosis (e) analysis of hUC-MSCs at various passages (P3, P6, P15) cultured in 10% FBS/DF12 medium by flow cytometry (mean ± SEM, n = 3). *P < 0.05; **P < 0.01; NS, not significant. f qRT-PCR analysis of pluripotency markers (POU5F1, SOX2, NANOG) in hUC-MSCs at various passages (P3, P6, P15) cultured in 10% FBS/DF12 medium. Data are shown as mean ± SEM (n = 3). *P < 0.05; NS, not significant. g Western blotting analysis of pluripotency markers (OCT4, SOX2, NANOG) in hUC-MSCs at various passages (P3, P6, P15) cultured in 10% FBS/DF12 medium. α-Tubulin was used as a loading control. h Quantitative analysis of OCT4, SOX2, and NANOG expression in hUC-MSCs (P3, P6, P15) cultured in 10% FBS/DMEM-F12 medium by gray scanning with ImageJ software (NIH). Data are shown as mean ± SEM (n = 3). *P < 0.05. i Karyotype analysis of hUC-MSCs at various passages (P3, P6, P15) cultured in 10% FBS/DF12 medium with G-banded chromosome experiment